Air Toxics: Also
known as toxic air pollutants or hazardous air pollutants,
these are chemicals that cause or may cause serious effects
in humans, and may be emitted into the air in quantities
that are large enough to cause those adverse health effects.
These effects cover a wide range of conditions from lung
irritation to birth defects to cancer. Health concerns may
be associated with both short and long term exposures to
these pollutants. Many are known to have respiratory, neurological,
immune or reproductive effects, particularly for more susceptible
sensitive populations such as children. 188 air toxics are
listed as "Hazardous
Air Pollutants" in the 1990 Clean Air Act.

Area Sources: Small
sources of air pollution which by themselves may not emit
very much, but when their emissions are added together they
may account for a sizable portion of the total emissions
of air toxics. In NATA, USEPA refers to this category as
"area and other sources," and includes small industrial
sources that fall below the "major souce" threshold. Included
in this category are: consumer products (personal care products,
household products, adhesives and sealants, automotive products,
coatings); residential heating and fuel use; pesticide use;
fires; gasoline stations; dry cleaners; chromium electroplating;
surface coating of cans and paper; metal parts cleaning;
metal recycling; small chemical manufacturing plants; and
bakeries, among others.

Background Concentration: The pollutant levels that are found throughout the continental
United States even in "clean air locations," areas where
no man-made air toxic emissions would be expected. They
are a result of past emissions of persistent pollutants,
long-range transport of recent emissions, and widespread
man-made sources.

Carcinogen: A chemical that has been shown to cause cancer, either
in people or animals.

CEP: USEPA's Cumulative
Exposure Project for 1990.

Chronic: long
duration or frequent recurrence.

Emissions Inventory: A list of activity categories that emit pollutants and
an estimate of how much is emitted by each.

Exposure: Contact
with a substance through inhalation, ingestion or some
other means for a specific period of time.

HAP: Hazardous air
pollutant. In general, an "air toxic." Specifically, this
also refers to one of the 188 specific pollutants listed in the 1990 Clean Air
Act amendments.

Health Benchmark: The chemical-specific air concentration below which there
should be no significant harm to human health. For a carcinogen
(cancer-causing chemical), the health benchmark is set
at the air concentration that over a lifetime would cause
no more than a one in a million increase in the likelihood
of getting cancer. For a noncarcinogen, the health benchmark
is the air concentration which is likely to cause no harm,
even if exposure occurs on a daily basis for a lifetime.

MACT: Maximum Achievable
Control Technology.

Major Sources: Defined
in the Clean Air Act as a facility that emits at least
10 tons per year of one HAP, or 25 tons per year of a
combination of HAPs. See also point
source.

Mobile Sources: A source of air pollution which can move from place to
place. In NATA, mobile sources are separated into on-road
sources (cars, trucks, buses, motorcycles) and non-road sources (airplanes, trains,
construction equipment, lawnmowers, boats, dirt bikes,
etc.).

NATA: National-Scale
Air Toxics Assessment. A project undertaken by USEPA in
which they estimate exposure to air toxics nationwide
for 1996. It consists of an inventory of air toxics emissions
from point, area, and mobile sources; dispersion modeling
of those emissions to estimate ambient air concentrations;
and estimates of the resulting risk to the population
nationwide.

NJDEP: New Jersey
Department of Environmental Protection

Noncarcinogen: A pollutant that can cause adverse health effects other
than cancer.

Ozone: an air pollutant
that is produced from other air pollutants and sunlight.
Unhealthy levels can occur during the summer in New Jersey.
Studies have shown that ozone causes asthma attacks. For
more information click here.

PAH: Polycyclic aromatic
hydrocarbons. 7 chemicals that are part of a class of
compounds called polycyclic
organic matter (POM). They are: benz[a]anthracene;
benzo[b]fluoranthene; benzo[k]fluoranthene; benzo[a]pyrene;
chrysene; dibenz[a,h]anthracene; and indeno[1,2,3-cd]pyrene.
They are all probable human carcinogens.

Particulate
matter: small particles suspended in the air
that are respiratory irritants. Some studies have associated
particulate matter with asthma attacks.

Particulates: Fine liquid or solid particles such as dust, smole, mist,
fumes or smog, found in the air or emissions.

Point Sources: A
stationary facility or process that emits a significant
amount of air pollution during manufacturing, power generation,
heating, incineration, or other such activity. In NATA,
USEPA used the term major
source and included in it just those sources which
emit at least 10 tons per year of any one hazardous air
pollutant (HAP), or at least 25 tons per year total of
any HAPs.

Pollutants: Unwanted chemicals or other materials found in the air.
Pollutants can harm health, the environment and property.
Many air pollutants occur as gases or vapors, but some
are very tiny solid particles: dust, smoke or soot.

POM: Polycyclic organic
matter. A broad class of compounds that is formed primarily
from combustion, and is present in the air in particulate
form. Sources are diverse and include vehicle exhaust,
fires, and hazardous waste sites. Because of limited emissions
data, for NATA, POM has been separated into two categories. 7-PAH consists of
7 species of POM (identified above and evaluated separately
in NATA).

Reference Concentration: (RfC) - An estimate (with uncertainty spanning about an
order of magnitude) of a continuous inhalation exposure
to the human population (including sensitive subgroups)
that is likely to be without an appreciable risk of harmful
effects during a lifetime. It can be derived from various
types of human or animal data, with uncertainty factors
generally applied to reflect limitations of the data used.

Risk Ratio: The comparison
of the measured or estimated air concentration of a specific
chemical to its health
benchmark to determine either the magnitude of the
risk of developing cancer or of some noncancer health
effect. If the risk ratio for a chemical is less than
one, the air concentration does not pose a health risk.
If it greater than one, it may be of concern. The risk
ratio shows just how much higher the air concentration
is than the health benchmark.

TRI:Toxic
Release Inventory. This is a database of information
about releases of more than 650 toxic chemicals from manufacturing
facilities throughout the United States.

Unit Risk Factor: The upper-bound excess lifetime cancer risk estimated
to result from continuous exposure to a chemical at a
concentration of 1 µg/m3 in air. For example, if the Unit
Risk Factor = 2 x 10-6 /µg/m3, then a person
exposed daily for a lifetime to 1 µg of the chemical in
1 cubic meter of air would have an increased risk of cancer
equal to 2 in a million.

Volatile Organic Compounds (VOCs): Organic chemicals all contain the element carbon(C); organic
chemicals are the basic chemicals found in living things
and in products derived from living things, such as coal,
petroleum and refined petroleum products. Many of the
organic chemicals we use do not occur in Nature, but were
synthesized by chemists in laboratories. Volatile chemicals
produce vapors readily; at room temperature and normal
atmospheric pressure, vapors escape easily from volatile
liquid chemicals. Volatile Organic chemicals include gasoline,
industrial chemicals such as benzene, solvents such as
toluene and xylene, and tetrachloroethylene (perchloroethylene,
the principal dry cleaning solvent). Many volatile organic
chemicals are also hazardous air pollutants; for example,
benzene causes cancer.